In processing lines where carton blanks are conveyed along a straight line path for folding and gluing, it is relatively straightforward to engage the leading and lateral edge panels or flaps with plows or shoes or the like and fold them into position for gluing. The trailing panels or flaps of carton blanks are more difficult to engage and fold because the blanks are moving in the direction of the fold and hence away from any folding mechanism.
A trailing edge folder for use in combination with a blank folding machine has recently been developed which overcomes this difficulty. The trailing edge folding mechanism includes an intermittently rotatable shaft mounted below and transverse to the horizontal path of the carton blanks. The shaft includes an arm or arms that extend generally radially from the shaft. The arms have folding heads at their distal ends for contacting and folding the trailing panels of successive blanks along fold lines parallel to the respective trailing edges. The shaft stops and pauses when a respective trailing edge is folded about 180.degree. on the fold line. After the panel is pulled from under a head and the blank is out of the path of the head, the shaft rotates further to a dwell position until the next blank appears along the path.
The machine just described is designed to operate automatically at a high rate, and may fold the trailing panels of more than ten cartons per second. The folding machine conveyor may travel at up to about 600 feet per minute. Proper operation of the machinery requires sophisticated apparatus for accurately and reliably controlling the operation of the trailing edge folder. The control apparatus should be adjustable for use at different operating speeds, and with differently sized carton blanks. It should also detect malfunctions, and provide diagnostic aids for maintenance.
Accordingly, an aspect of this invention is to provide new and improved control apparatus for a trailing edge folder in carton manfacturing machinery.
Another aspect is to provide new and improved control apparatus for a trailing edge folder which incorporates the features just described.